Rewritable medium recording apparatus

ABSTRACT

When a visible image on a printing area of a rewritable recording medium is erased by an erase head, a control unit and an erasing control device, respectively, control the electric current supplied to the erase head, based on a power supply pattern recorded in a storage device and a temperature information from a first temperature detecting device for measuring the ambient temperature.

BACKGROUND OF THE INVENTION

This invention relates to a rewritable medium recording apparatus whichcan handle a card having a thermally reversible color developing layer.

Recently, there have been widely spread rewritable medium recordingapparatuses of the type having, in addition to the function of recordingand reproducing magnetic information by means of a magnetic head, arewrite function by which the information printed can be rewritten overand over by means of a thermal head and an erase head, in order tohandle a card having a thermally reversible color developing layer onwhich the information is visible as characters. The card systemcomprising the combination of such card and rewritable medium recordingapparatus can be applied to a broad field including the point cardsystem for shopping center, card system for staff's cafeteria and cardsystem for the rental business, by making use of the characteristic thatthe information is visible.

A summary of thermally reversible color developing layer of such cardwill be described with reference to FIG. 9 which is a plan view of acard having a thermally reversible color developing layer and FIG. 10which is a characteristic diagram showing the color developing/erasingcharacteristics of the thermally reversible color developing layer.

In FIG. 9, a card 1 has a thermally reversible color developing layerformed on the entire silver base, and is printed except in a printableprinting area 1a. Since the printing area 1a is normally transparent, itappears silver which is the color of the base, but when it is heated ata predetermined temperature, heated portions turn white so that whitecharacters appear on the silver background. The card 1 is formed on theback thereof, opposite to the printing area 1a, with a recording layeron which information can be recorded by making use of the magnetism.

The thermally reversible color developing layer is summarized asfollows. As shown in FIG. 10, distributed in the thermally reversiblecolor developing layer is a low-molecular substance having the propertythat the crystal structure thereof is changed when receiving the thermalenergy. In the condition shown at a point A, since the crystal structureof the low-molecular substance is in the large single crystal state, thelight is allowed to transmit so that the thermally reversible colordeveloping layer appears to be transparent. On the other hand, in thecondition shown at a point B, the crystal structure is in thepolycrystal state, and therefore the light is scattered to cause thethermally reversible color developing layer to become opaque, with theresult that the thermally reversible color developing layer appearswhite.

Explaining this phenomenon in connection with the colordeveloping/erasing characteristics, if a card in the transparentcondition shown at the point A is heated, it starts to become opaque attemperatures 90 to 100° C. and, If cooled down to room temperature fromthis condition, it is turned into the completely opaque condition asshown at the point B. On the other hand, if the card in the opaquecondition shown at the point B is heated, it is turned into thetransparent condition at temperatures around 80° C., and therefore it ispossible to reversibly perform the color developing/erasing process byrepeated change in condition between transparent and opaque.

Now, the structure of a conventional rewritable medium recordingapparatus will be described. FIG. 11 is a schematic view showing thestructure of the conventional rewritable medium recording apparatus, andFIG. 12 is a plan view of a card used for the conventional rewritablemedium recording apparatus.

In FIGS. 11 to 12, a rewritable medium recording apparatus 2 comprises arecording head 3 by which at least one of recording and reproduction ofinformation on a recording layer of a card 1 is performed by making useof magnetism, a printing unit 5 having a print head 4 by whichinformation is printed on a thermally reversible color developing layerof the card 1, and an erasing unit 7 having an erase head 6 by which theinformation printed on the thermally reversible color developing layeris erased. The card 1 used for the rewritable medium recording apparatus2 has a thermally reversible color developing layer on one surface and arecording layer on the other on which information can be recorded,reproduced and erased by means of the recording head 3. By heating aprinting area 1a on the thermally reversible color developing layer bymeans of the print head 4, characters are printed white to becomevisible.

The card 1 is inserted in a slot 8 of the printing unit 5 with itsprinting area 1a facing up and caused to reciprocate twice by means offeed rollers 9 to 11 driven by drive means (not shown), during which allprocess is completed.

In the first reciprocation, at least one of recording and reproductionof information on the recording layer on the back of the card 1 isperformed by means of the recording head 3, while the card 1 is conveyedforward by the feed rollers 9 to 10. Then, the card 1 is fed into theerasing unit 7 by the feed rollers 11 for the purpose of erasing theinformation printed. When the card 1 is brought to a stop in the erasingunit 7, a table 13 adapted to be moved up and down by a solenoid 12 ismoved upward until the printing area 1a of the card 1 is pressed againstthe erase head 6 heated to a temperature around 80° C., thereby erasingthe information printed. In this case, the whole printing area 1a of thecard 1 is subjected to erasing because the width of the printing area 1ain the longitudinal direction of the card 1 coincides with the width ofthe erase head 6. After the above process is completed, the feed rollers11 are rotated reversely so that the card 1 is fed back into theprinting unit 5 again to make ready for the printing process.

In the second reciprocation, character information is written in turn onthe printing area 1a on the front of the card 1 by means of the printhead 4 in the printing unit 5. The print head 4 is enabled to move upand down when being driven by a solenoid 14. When the card 1 is on theplaten roller 15, the print head 4 is lowered to be pressed against theprinting area 1a and then a large number of heating resistance elementsof the print head 4 are heated to a temperature around 100° C. accordingto the print pattern, thereby printing optional characters, figures andthe like on the printing area 1a of the card 1. After the above processis completed, the card 1 is conveyed by the feed rollers 9 to 10 so asto be caused to pass over the recording head 3. While the feed rollers 9to 10 are rotated reversely to cause the card 1 to pass over therecording head 3, the information recorded is verified. Thereafter, thecard 1 is released out of the slot 8.

However, in the conventional rewritable medium recording apparatusdescribed above, when erasing the information printed on the card 1 inthe erasing unit 7, the printing area 1a of the card 1 shown in FIG. 12is subjected to erasing over a wide range all at once by means of thestamp type erase head 6. This inevitably causes the erasing unit 7 to beincreased in size, and therefore it has been necessary to provide theerasing unit 7 separately from the printing unit 5. Further, since thecard 1 fed into the erasing unit 7 must be fed back into the printingunit 5 after the erasing process, the card 1 should undergo the erasingprocess while being held between the feed rollers 11. For this reason,since it is necessary For the card 1 to reserve a space for holding, aconsiderably wide area is occupied by unusable portion, giving rise to aproblem that the printing area 1a that can be set on the card 1 (in FIG.12, approx. 40 mm long in the longitudinal direction of the card 1)should inevitably be narrowed.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a rewritable mediumrecording apparatus which is capable of handling a card having a wideprinting area while overcoming the above problem.

It is another object of the invention to provide a compact rewritablemedium recording apparatus.

It is still another object of the invention to provide a low-powerrewritable medium recording apparatus.

A further object of the invention is to provide a rewritable mediumrecording apparatus which is capable of recording and erasing visibleimages with certainty.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic structural view of a rewritable medium recordingapparatus according to a first embodiment of the present invention;

FIG. 2 is a schematic plan view showing essential portions of therewritable medium recording apparatus according to the first embodimentof the invention;

FIG. 3 is a plan view of a card used for the rewritable medium recordingapparatus according to the first embodiment of the invention;

FIG. 4 is a schematic view showing the behavior of erase and print headsof the rewritable medium recording apparatus according to the firstembodiment of the invention;

FIG. 5 is a schematic view showing the behavior of the erase and printheads of the rewritable medium recording apparatus according to thefirst embodiment of the invention;

FIG. 6 is a schematic view showing the behavior of a lock mechanism ofthe rewritable medium recording apparatus according to the firstembodiment of the invention;

FIG. 7 is a schematic view showing the behavior of the lock mechanism ofthe rewritable medium recording apparatus according to the firstembodiment of the invention;

FIG. 8 is a schematic view showing the behavior of the lock mechanism ofthe rewritable medium recording apparatus according to the firstembodiment of the invention;

FIG. 9 is a plan view of a card having a thermally reversible colordeveloping layer;

FIG. 10 is a characteristic diagram showing the color developing/erasingcharacteristics of the thermally reversible color developing layer;

FIG. 11 is a schematic view of a conventional rewritable mediumrecording apparatus;

FIG. 12 is a plan view of a card used for the conventional rewritablemedium recording apparatus;

FIG. 13 is a sectional view of a rewritable medium recording apparatusaccording to a second embodiment of the present invention;

FIGS. 14A and 14B are illustrations showing an erase head used in therewritable medium recording apparatus according to the second embodimentof the invention;

FIG. 15 is a plan view of the erase head used in the rewritable mediumrecording apparatus according to the second embodiment of the invention;

FIG. 16 is a block diagram of the rewritable medium recording apparatusaccording to the second embodiment of the invention;

FIG. 17 is a graph showing a waveform of electric current applied to theerase head of the rewritable medium recording apparatus according to thesecond embodiment of the invention;

FIG. 18 is a graph showing a waveform of electric power applied to theerase head of the rewritable medium recording apparatus according to thesecond embodiment of the invention versus surface temperature of theerase head; and

FIG. 19 is a graph showing the relationship between the density ofvisible image on the rewritable recording medium according to the secondembodiment of the invention and temperature applied to the recordingmedium.

DETAILED DESCRIPTION OF THE INVENTION

Now, a first embodiment of the present invention will be described withreference to FIGS. 1 to 8 in which the same components as theconventional apparatus are designated by the same reference numerals.

(Embodiment 1)

FIG. 1 is a schematic view showing the structure of a rewritable mediumrecording apparatus according to a first embodiment of the presentinvention, FIG. 2 is a schematic plan view showing essential portions ofthe rewritable medium recording apparatus according to the firstembodiment of the invention, and FIG. 3 is a plan view of a card usedfor the rewritable medium recording apparatus according to the firstembodiment of the invention. FIGS. 4 and 5 are schematic views showingthe behavior of erase and print heads of the rewritable medium recordingapparatus according to the first embodiment of the invention.

In FIGS. 1 to 3, a rewritable medium recording apparatus 22 comprises arecording head 3 by which at least one of recording and reproduction ofinformation on a recording layer of a rewritable recording medium 21 isperformed by making use of magnetism, a print head 23 by whichinformation is printed on a thermally reversible color developing layerof the rewritable recording medium 21, and an erase head 24 by which theinformation printed in the thermally reversible color developing layeris erased. The print head 23 and the erase head 24 are connected bymeans of a pin 25 so that a driving mechanism 26, which is to bedescribed later, causes the two heads to come into and out of contactwith the rewritable recording medium 21 in cooperation with each other.The rewritable recording medium 21 used for the rewritable mediumrecording apparatus 22 has a thermally reversible color developing layeron one surface thereof and a recording layer on the other thereof onwhich information can be recorded and reproduced by means of therecording head 3. By heating a printing area 21a on the thermallyreversible color developing layer by means of the print head 23,characters are printed white to become visible.

The rewritable recording medium 21 is inserted into a slot 8 of therewritable medium recording apparatus 22 with its printing area 21afacing up. Provided in the vicinity of the slot 8 is a discharge brush8a as an example of discharge means in order to remove the staticelectricity charged on the rewritable recording medium 21. The dischargebrush 8a needs not be always provided in the vicinity of the slot 8 butmay be provided at any appropriate location on the conveying path forthe rewritable recording medium 21. Since the static electricity of therewritable recording medium 21 can be removed by the discharge functionof the discharge brush 8a, adverse effect of the static electricity onthe recording layer formed on the back of the rewritable recordingmedium 21 can be prevented as much as possible. The rewritable recordingmedium 21 inserted into the slot 8 is caused to reciprocate twice bymeans of feed rollers 9 to 11 driven by drive means (not shown), duringwhich all process is completed.

In the first recipocation, while the rewritable recording medium 21 isconveyed forward at high speed (approx. 400 mm/sec) by the feed rollers9 to 11, at least one of recording and reproduction of information onthe recording layer on the back of the recording medium is performed bythe recording head 3, and then the rewritable recording medium 21 isconveyed backward at high speed again until it returns to its initialstate in which it is held between the feed rollers 9 to 10.

In the second reciprocation, in order to erase and print information onthe thermally reversible color developing layer of the printing area21a, the rewritable recording medium 21 is conveyed forward at highspeed to a predetermined position located on platen rollers 24p, 23p. Assoon as the rewritable recording medium 21 arrives at the predeterminedposition where the information is to be erased and printed, conveyanceof the rewritable recording medium 21 is changed from high-speedconveyance to low-speed conveyance (approx. 30 mm/sec). As shown inFIGS. 4 to 5, a lift cam 26c is rotated through reduction gears 26b bymeans of a motor 26a of the driving mechanism 26. Then, a spring 24s forpressing down the erase head 24 and a spring 23s for pressing down theprint head 23 cooperate to lower the erase head 24 and the print head23. In this condition, as shown in FIG. 3, the erase head 24 is firstheated to a temperature around 80° C. to erase only the selectedportions in the printing area 21a of the rewritable recording medium 21conveyed, and then the print head 23 is heated to a temperature around100° C. to print optional characters, figures and the like only on theselected portions in the printing area 21a. After the above process iscompleted, the feed rollers 9 to 11 are rotated reversely so that therewritable recording medium 21 is conveyed backward at high speed untilit is released out of the slot 8. While the rewritable recording medium21 passes over the recording head 3, the information recorded isverified.

As described above, the rewritable medium recording apparatus 22 hassuch a structure that both of the erase head 24 and the print head 23are moved up and down by the driving mechanism 26 alone, and thereforeit becomes possible to simplify the driving mechanism 26 by which theerase and print heads are caused to come into and out of contact withthe rewritable recording medium 21. Further, since the erase head 24 andthe print head 23 are rotatably mounted on a shaft 24a and a shaft 23a,respectively, the two heads are allowed to tilt independently of eachother, thereby making it possible to obtain the optimum contact betweenthe two heads and the rewritable recording medium 21. If it is possibleto obtain the optimum contact, that is, if the two heads can perfectlycome into close contact with the rewritable recording medium 21, theprinting area 21a of the rewritable recording medium 21 can besufficiently heated by the two heads. This eliminates the occurrence ofdefects such as incomplete erasing and unclear print.

As shown in FIGS. 4 to 5, the rewritable medium recording apparatus 22has the structure that the erase head 24 and the print head 23 are movedup and down simultaneously, and therefore printing cannot be effectedbefore and behind the rewritable recording medium 21 over a certainrange as shown in FIG. 3, which corresponds to a distance L between thecenter of the erase head 24 and the center of the print head 23 shown inFIG. 2. For this reason, since the erase head 24 and the print head 23are arranged as close as possible in order to widen the printing area21a, the printing area 21a can be secured about 60 mm in thelongitudinal direction of the rewritable recording medium 21, which isone and a half times the size of the printing area of about 40 mm in theconventional card.

By the way, in the above-mentioned second reciprocation, when printing,the rewritable recording medium 21 receives a load given by the erasehead 24 and the print head 23 at front and rear portions thereofcorresponding to the two heads. When the diameter of the platen roller24p for the erase head 24 is larger than the diameter of the platenroller 23p for the print head 23 due to variation in diameter of theplaten rollers 24p, 23p or the like, there is produced a difference inconveying speed between the platen rollers 24p and 23p, whereby therewritable recording medium 21 cannot be regularly conveyed. This causesthe rewritable recording medium 21 to be pushed from behind. For thisreason, the print head 23 is not allowed to sufficiently heat theprinting area 21a, resulting in print skip in the form of a line.

In order to prevent such print skip, it suffices to subordinate theconveying speed of the platen roller 24p for the erase head 24 to theconveying speed of the platen roller 23p for the print head 23 at alltimes. For this purpose, the force of the spring 23s for pressing downthe print head 23 is increased so that the load given to the rewritablerecording medium 21 by the print head 23 exceeds the load given by theerase head 24. By doing so, even if the conveying speed of the platenroller 24p becomes higher than that of the platen roller 23p, the platenroller 24p is caused to idle, thereby making it possible to regulate theconveying speed.

Allowing for maintenance, an upper unit of the rewritable mediumrecording apparatus 22 is so attached as to be opened and closed about ashaft 22a in the direction shown by the arrow, as shown in FIG. 1.However, if the upper unit can be opened and closed too easily, when therewritable medium recording apparatus 22 is opened by mistake while therewritable recording medium 21 is being processed, the informationstored on the recording layer of the rewritable recording medium 21 canbe destroyed. To cope with this, the rewritable medium recordingapparatus 22 is provided with a lock mechanism which can be released bysomething nearby.

Now, description will be given of the lock mechanism with reference toFIGS. 6 to 8 which are schematic views showing the behavior of the lockmechanism of the rewritable medium recording apparatus according to thefirst embodiment of the present invention.

As shown in FIG. 6, the lock mechanism of the rewritable mediumrecording apparatus 22 is incorporated in the upper unit of therewritable medium recording apparatus 22 and functions in such a mannerthat a hook portion 34 of a hook member 33 engages with a fixed pin 35of a lower unit of the rewritable medium recording apparatus 22, thehook member 33 being pulled by a spring 31 at one end with the centralportion thereof supported by a fulcrum pin 32. The one end of the hookmember 33 is caught by a stopper 37 extending from a lock button 36. Asshown in FIG. 7, if is like a coin is inserted into a slot 36a of thelock button 36 and rotated counterclockwise, the hook member 33 isrotated to allow the hook portion 34 to be disengaged from the fixed pin35. Then, as shown in FIG. 8, locked condition is released and the upperunit of the rewritable medium recording apparatus 22 may be opened. Thislock mechanism has a feature in that it is secure since the lockedcondition cannot be released unless something is inserted to rotate thelock button 36, and that the locked condition can be easily releasedonly by a person having an aim of releasing the locked condition becausethe lock button 36 can be rotated by inserting something nearby like acoin.

As described above, according to the present invention, in therewritable medium recording apparatus comprising the recording head bywhich at least one of recording and reproduction of information on therecording layer of the card is performed, the print head by whichinformation is printed on the thermally reversible color developinglayer of the card, and the erase head by which the information printedon the thermally reversible color developing layer is erased, the erasehead and the print head are so connected as to come into and out ofcontact with the card in cooperation with each other in anindependently, inclined condition, and a single driving mechanism isused to cause the erase head and the print head to come into and out ofcontact with the card, and therefore it is possible to provide arewritable medium recording apparatus which is capable of handling acard having a wide printing area and in which the casing is reduced insize.

(Embodiment 2)

In FIG. 13, the reference numeral 21 denotes a rewritable recordingmedium; 108, a travelling path provided for the rewritable recordingmedium 21 to move in the rewritable medium recording apparatus; and 109,110, driving rollers which are rotatively driven by a motor (not shown)or the like. Driven rollers 111, 112 are provided facing of the drivingrollers 109, 110, respectively, with the travelling path 108 interposedtherebetween. The rewritable recording medium 21 is taken into therewritable medium recording apparatus by means of the driving rollers109, 110 and the driven rollers 111, 112.

The reference numeral 113 denotes a magnetic head facing on thetravelling path 108. The magnetic head 113 reads and writes data fromand on a recording area 21b of the rewritable recording medium 21. Inthe case of this embodiment, if the magnetic head used as means forrecording and reproducing data, data is magnetically recorded on therecording area 21b as a matter of course. In the present embodiment,description has been made as to the case where data is magneticallyrecorded on and reproduced from the rewritable recording medium 21, andhowever data may be optically read by means of an optical pickup or thelike instead of the magnetic head 113 (it is a matter of course thatdata is optically recorded on the recording area 21b). In cases wheredata is optically recorded and reproduced by means of the optical pickupor the like, it is possible to deal with a large volume of data.

Furthermore, by mounting IC memory on the rewritable recording medium21, data can also be electrically recorded and reproduced. In this case,it is necessary to transmit and receive signals with IC memory insteadof the magnetic head 113. If data is electrically recorded andreproduced in this way, a large volume of data can be dealt with anddata can be written on and read from the IC memory at high speed.

A pressure roller 114 is provided facing on the magnetic head 113 withthe travelling path 108 interposed therebetween so that the rewritablerecording medium 21 is held between the pressure roller 114 and themagnetic head 113 so as to bring the magnetic head 113 into closecontact with the recording area 21b.

The reference numeral 115 denotes a thermal head for forming a visibleimage on the printing area 21a of the rewritable recording medium 21.The thermal head 115 is provided with a thermistor (not shown) formeasuring the ambient temperature. The thermal head 115 may be one thathas substantially the same structure as the usual thermal head used forthe thermosensitive recording. In this case, the thermistor of thethermal head 115 is used for measuring the ambient temperature,controlling the applied voltage and the like of the thermal head 115,controlling the amount of heat generated by a large number of dotheating elements of the thermal head 115 and so on.

The reference numeral 116 denotes a platen roller provided facing on thethermal head 115 with the travelling path 108 interposed therebetween.The platen roller 116 is rotatively driven by a motor (not shown) or thelike. The rewritable recording medium 21 is held between the platenroller 116 and the thermal head 115 so that the thermal head 115 isbrought into close contact with at least the printing area 21a of therewritable recording medium 21 to partially heat the printing area 21ato a predetermined temperature, thereby causing a good visible image toappear on the printing area 21a.

The reference numeral 117 denotes an erase head for erasing the visibleimage displayed on the printing area 21a of the rewritable recordingmedium 21. The erase head 117 has a structure shown in FIGS. 14 and 15.In FIGS. 14A, 14B and 15, the reference numeral 118 denotes a base platemade of alumina or the like, the base plate 118 being fitted on a holder118a. A heat storage layer 119a is provided on the base plate 118, and athick-film heater 119 is formed on the heat storage layer 119a. Further,a protective layer 120 is formed on the thick-film heater 119 except atend portions of the thick-film heater 119. The thick-film heater 119 ismade of a material of silver-palladium group, for example, and theprotective layer 120 is generally made of amorphous glass. Thethick-film heater 119 is applied with a predetermined electric currentin the form of a rectangular wave by erasing drive means, which is to bedescribed later, so as to be heated. A thermistor 121 for measuring thetemperature of the thick-film heater 119 is provided on the side of thebase plate 118 opposite to the side on which the thick-film heater 119is provided. The thermistor 121 is put in a cavity or a hole formed inthe holder 118a while being kept in direct contact with the base plate118. It is essentially desirable that the thermistor 121 measures thetemperature of the protective layer 120, but the protective layer 120 isbrought into direct contact with the rewritable recording medium 21 topreclude actually arranging the thermistor 121 on the side of thethick-film heater 119. Accordingly, the thermistor 121 measures thetemperature of the base plate 118 instead of the temperature of theprotective layer 120, taking notice of the fact that the temperature ofthe base plate 118 and the temperature of the protective layer 120 arecorrelated. The reference numerals 119b, 119c denote electrode portionsprovided at opposite ends of the thick-film heater 119. Lead wires andthe like are connected to each of the electrode portions 119b, 119c.

The reference numeral 122 denotes a platen roller provided facing on theerase head 117 with the travelling path 108 interposed therebetween. Theplaten roller 122 is rotatively driven by a motor (not shown) or thelike. The rewritable recording medium 21 is held between the platenroller 122 and the erase head 117 so that the erase head 117 is broughtinto close contact with the printing area 21a of the rewritablerecording medium 21 to heat the whole printing area 21a up to apredetermined temperature, thereby erasing the visible image on theprinting area 21a.

The reference numeral 123 denotes a driving roller which is rotativelydriven by a motor (not shown) or the like. The driving roller 123cooperates with a driven roller 124, which is provided facing thereonwith the travelling path 108 interposed therebetween, to allow therewritable recording medium 21 to move along the travelling path 108.

Incidentally, the driving rollers 109, 110, 123 and the platen rollers116, 122 are rotatively driven by a common motor (not shown) while beingsynchronized with each other through the medium of belts, gears and soon, which makes it possible to simplify the structure and realize thestable movement of the rewritable recording medium 21 along thetravelling path 108.

The reference numerals 125, 126, 127, 128 and 129 denote sensors formeasuring moving positions and the like of the rewritable recordingmedium 21, the sensors 125, 126, 127, 128 and 129 comprisingphotosensors or the like.

Operation and the like of the rewritable medium recording apparatusconstructed as described above will be described with reference to FIGS.13 to 16.

First of all, when position detecting means 130 comprising the sensors125, 126, 127, 128 and 129 detects insertion of the rewritable recordingmedium 21 into the apparatus, a control unit 131 sends a signal toconveyance drive means 132 so as to drive the motor (not shown) or thelike to rotate the driving rollers 109, 110, 123 and the platen rollers116, 122. Then, the rewritable recording medium 21 begins to move alongthe travelling path 108 while being held between the driving rollers109, 110 and the driven rollers 111, 112.

The recording area 21b of the rewritable recording medium 21 firstslides on the magnetic head 113. The control unit 131 sends a controlsignal to data read/write means 133 to permit the magnetic head 113 toread out the data recorded on the recording area 21b. Reproduced signalread out at this time is transmitted to an external apparatus or thelike, for example.

The rewritable recording medium 21 is conveyed as far as the sensor 129.At this time, the thermal head 115 and the erase head 117 are retreatedfrom the travelling path 108.

When the sensor 129 detects that the rewritable recording medium 21reaches as far as the sensor 129, the position detecting means 130outputs a signal to the control unit 131. On receiving the signal, thecontrol unit 131 sends a control signal to the conveyance drive means132 so as to stop the operation of the motor (not shown) or the like. Inconsequence, the driving rollers 109, 110, 123 and the platen rollers116, 122 are stopped in rotatively driven movement to cause therewritable recording medium 21 to stand by at the end of the travellingpath 108.

The control unit 131 sends control signals to erase head drive means 134and printing drive means 135 so that unillustrated driving means (motor,solenoid and the like) are operated to cause the erase head 117 and thethermal head 115 to hang out against the travelling path 108.

Subsequently, the control unit 131 outputs signals to erasing controlmeans 136 and printing control means 139. On receiving the signal fromthe control unit 131, the erasing control means 136 starts to supplyelectric current to the erase head 117. This electric current is in theform of a rectangular wave as shown in FIG. 17. The erasing controlmeans 136 controls the durations L1 and L2 of two fixed values of therectangular wave so as to supply the electric current to the erase head117 (actually to the thick-film heater 119). Current supply pattern isas shown in FIG. 17.

As shown in FIG. 18, in a state that the rewritable recording medium 21stands by at the end of the travelling path 108, the control unit 131outputs a control signal to the erasing control means 136 so as to setan initial heating mode. At this time, in the initial heating mode, theerasing control means 136 applies an electric current with duty ratioL1:L2=9:1˜10:0 as shown in FIG. 18 to the erase head 117 to heat thesame. In this embodiment, L2 is 0 (zero). One hundred percent duty ratioshown in FIG. 18 means that L1:L2=10:0, that is, L2 is 0 (zero). Then,second temperature detecting means 137 receives a signal correlated withthe temperature output by the thermistor 121 shown in FIG. 14 to send afirst temperature signal to the control unit 131 on the basis of theinformation from the thermistor 121. The control unit 131 heats theerase head 117 as high as a predetermined temperature at one hundredpercent duty ratio while making reference to the first temperaturesignal. As soon as the control unit 131 recognizes from the firsttemperature signal that the erase head 117 reaches the erasingtemperature (the temperature at which the printing area 21a of therewritable recording medium can be erased), the control unit 131 outputsa control signal to the erasing control means 136 so as to set astand-by mode. On receiving this signal, the erasing control means 136supplies the electric current to the erase head 117 at a duty ratio of15 to 23% (L1:L2=15˜23:85˜77). Such variation of the electric currentkeeps the erase head 117 at the erasing temperature. At this time, theerasing control means 136 changes the duty ratio of the electric currentapplied to the erase head 117 referring to the first temperature signalso as to keep the erasing temperature.

When the erase head 117 enters into the stand-by mode, the control unit131 sends a control signal to the conveyance drive means 132 so as torotatively drive the driving rollers 109, 110, 123 and the platenrollers 116, 122 to cause the rewritable recording medium 21 to movetoward the sensor 125. Then, the rewritable recording medium 21 startsto come in contact with the erase head 117.

After the sensor 129 detects that the rewritable recording medium 21starts to move, the sensor 128 immediately in front of the erase head117 detects the rewritable recording medium 21, and outputs a detectionsignal to the control unit 131 via the position detecting means 130. Thecontrol unit 131 then outputs a control signal to the erasing controlmeans 136 so as to set an erasing mode. On receiving this controlsignal, the erasing control means 136 supplies the electric current tothe erase head 117 so that the duty ratio becomes higher than that inthe stand-by mode (that is, the duration L1 is made longer to preventthe temperature drop of the erase head 117 caused by contact with therewritable recording medium 21).

At this time, the duty ratio of the electric current is determined asfollows. First of all, the erasing control means 136 reads out throughthe control unit 131 these data which relates to the duty ratio of theelectric current in the erasing mode (referred to as correction data,hereinafter) and stored in memory means 138. The correction data havebeen previously prepared for correction of a decrease in erasingtemperature attributed to materials of the rewritable recording medium21 and the erase head 117, area of contact between the erase head 117and the rewritable recording medium 21 and so on. Further, based on thetemperature information measured by the thermistor provided on thethermal head 115 for measuring the ambient temperature, a firsttemperature detecting means 139a outputs a second temperature signalwhich in turn is input to the erasing control means 136.

The erasing control means 136 decides the duty ratio of the electriccurrent in the erasing mode referring to the correction data from thememory means 138 and the second temperature signal. This is because theerasing temperature may possibly be somewhat changed depending upon theambient temperature. Actually, however, since the correction data areprepared on the basis of room temperature, there is no possibility thatthe second temperature signal causes a large deviation from the dutyratio of the correction data. Incidentally, even in this case, the firsttemperature signal is referred to, and the temperature control isperformed even when the temperature of the erase head 117 is suddenlychanged. Such control can correct the erasing temperature drop and thelike which can be caused by the ambient temperature and the contactbetween the rewritable recording medium 21 and the erase head 117,thereby preventing the temperature of the erase head 117 from deviatingfrom the erasing temperature. It is therefore possible to obtain thestable erasing characteristic. Further, since the ambient temperature ismeasured by the thermistor equipped beforehand to the thermal head 115,the number of component parts can be reduced.

Incidentally, in the present embodiment, the duty ratio is decided onthe basis of the correction data and the second temperature signal.However, it is also possible that, data prepared for correction of adecrease in erasing temperature, which may be caused by the materials ofthe rewritable recording medium 21 and the erase head 117, area ofcontact between the erase head 117 and the rewritable recording medium21 and so on, may be previously stored in an amount corresponding to theambient temperature so that the data on the present ambient temperatureis read out from the memory means 138 in response to the secondtemperature signal.

Immediately after the print on the printing area 21a of the rewritablerecording medium 21 is erased by the erase head 117 in theabove-described manner, a predetermined visible image is formed on theprinting area 21a by means of the thermal head 115. At this time,referring to the data stored in the memory means 138, the datatransmitted from the external apparatus and so on, the printing controlmeans 139 causes the dot heating elements of the thermal head 115 togenerate heat to form the visible image on the printing area 21a.

After the predetermined visible image is formed on the printing area21a, when the rewritable recording medium 21 passes over the magnetichead 113, the control unit 131 outputs a control signal to dataread/write means 133 so as to write a predetermined data. In response tothis signal, the data read/write means 133 writes the predetermined dataon the recording area 21b by means of the magnetic head 113, and thenthe rewritable recording medium 21 is released out of the travellingpath 108.

As has been described above, according to the present embodiment, it ispossible to stably erase and form the visible image on the printing area21a and provide the remarkable advantage of reducing the cost due to thedecrease in the number of component parts and the like.

Further, even for use in the general market where the interval betweenrecording and erasing of the visible image cannot be specified, it isunavoidable to erase at the fixed erasing temperature. Even if theerasing temperature range is a little shifted the existence of someerasable range of the recording medium itself in most cases enableerasing at the fixed erasing temperature only by means of the erase head117 provided that the erasing temperature is in that range. However, ifa shift of erasing temperature range causes the fixed erasingtemperature to be out of that range, the visible image to be erased isleft unerased, and therefore another visible image recorded succeedinglyis superimposed on the unerased image, resulting in a problem that itbecomes hard to recognize the visible image.

To cope with this, whether or not the visible image is left unerasedafter being erased by means of the erase head 117, when forming a newvisible image by the thermal head 115, the portion on which the newvisible image is to be formed is heated to the extent that the recordingmedium is allowed to develop color, while the other portion is heated upto the erasing temperature. Such control in this way makes the timeinterval between the previous heating and the next heating constant, sothat the erasing temperature always falls within the range shown bysolid line in FIG. 19, and therefore the fixed erasing and recordingtemperatures are serviceable at all times to make it possible to eraseand record in a stable manner.

Further, in cases where the rewritable medium recording apparatus has amagnetic recording device such as the magnetic head 113 as in thepresent embodiment, provision of the recording area 21b on therewritable recording medium 21 makes it feasilble to magnetically recordthe date and time of the recording of a visible image on the recordingarea 21b when the visible image is recorded. When erasing the visibleimage, the magnetic data is read in first of all. The data for the dateand time of the last recording of the visible image thus obtainedindicates how much the optimum erasing temperature for the visible imageis shifted, and therefore it is possible to decide the optimum erasingtemperature for the visible image on the recording medium inserted inthe recording apparatus. Moreover, even in cases where the optimumrecording and erasing temperatures for the visible image differaccording to the type of rewritable recording medium 21, the type ofrewritable recording medium 21 is magnetically recorded on the recordingarea 21b when recording a visible image. When erasing and recording thevisible image at the next time, the magnetic data is read in first. Thedata on the type of rewritable recording medium thus obtained enablesdeciding the erasing and recording temperatures for the visible image.

According to the present invention, the rise time elapsing from theinstant at which the power is turned on is reduced to eliminateconsumption of wasteful power in the stand-by condition as compared withthe conventional recording apparatus. In addition, it is possible toerase and record the visible image with certainty. Further, in thevisible image recording apparatus comprising thermal energy supply meanssuch as a thick-film heater capable of substantially erasing the visibleimage recorded on the recording medium in three heating modes includinginitial heating, stand-by and erasing modes, recording means such as athermal head for erasing the visible image left unerased by the thermalenergy supply means and for overwriting and recording of a new visibleimage at the same time, and magnetic recording device such as a magnetichead, provision of the magnetic recording layer on the recording medium,makes it feasible to magnetically record the date and time of therecording of the visible image on the magnetic recording layer formed onthe recording medium when the visible image is recorded, so that whenthe visible image is erased at the next time, it is possible to decidethe optimum erasing temperature for the visible image according to thedata on the date and time of the earlier magnetic recording. Moreover,even in cases where the optimum recording and erasing temperatures forthe visible image differ according to the type of recording medium, suchprovision of the magnetic recording layer on the recording medium makesit the type of recording medium possible to magnetically record on themagnetic recording layer when a visible image is recorded, so that it ispossible to decide the erasing and recording temperatures for thevisible image according to the data on the type of recording mediummagnetically recorded on the magnetic recording layer when the visibleimage is erased and recorded at the next time.

(Embodiment 3)

An apparatus in which the first and second embodiments are combined canobtain a further useful effect. Namely, the apparatus of the firstembodiment modified so as to perform the thermal control in the samemanner as the second embodiment makes it feasible to reduce the size ofthe apparatus and perform the erasing and recording of the visible imagewith certainty. In other words, if the thermal control performed by theerase head 24 and the print head 23 in the first embodiment is performedby means of the thermal head 115 and the erase head 117 described in thesecond embodiment, it is possible to obtain a compact and low-powerconsumption apparatus capable of erasing and recording the visible imagewith certainty.

What is claimed is:
 1. A rewritable medium recording apparatuscomprising:a travelling path along which a rewritable recording mediumis moved; recording means for performing at least one of reproductionand recording of data on a recording area of the rewritable recordingmedium; image forming means for forming a predetermined visible image byheating the rewritable recording medium up to a first temperature;erasing means for erasing the visible image formed on the rewritablerecording medium by heating the rewritable recording medium up to asecond temperature; first temperature detecting means for measuring theambient temperature to output an ambient temperature signal; storagemeans for storing a temperature control pattern for said erasing means;and a control unit for controlling an amount of heat applied to therewritable recording medium on said erasing means referring to saidambient temperature signal and the temperature control pattern stored insaid storage means so as to keep the rewritable recording medium at thesecond temperature to erase the visible image on the rewritablerecording medium by said erasing means.
 2. A rewritable medium recordingapparatus according to claim 1, further comprising second temperaturedetecting means for measuring the temperature of the erasing means tooutput an erasing temperature signal, and wherein the control unitcauses the erasing means to erase the visible image on the rewritablerecording medium, referring to the ambient temperature signal, erasingtemperature signal and temperature control pattern stored in saidstorage means.
 3. A rewritable medium recording apparatus according toclaim 1, wherein the erasing means comprises a thick-film heater and theimage forming means comprises a thermal head.
 4. A rewritable mediumrecording apparatus according to claim 3, wherein electric current ofrectangular waveform is supplied to the thick-film heater for control ofheating.
 5. A rewritable medium recording apparatus according to claim4, wherein the thermal control mode for the thick-film heater includesan initial heating mode, a stand-by mode and an erasing mode, and theelectric current of rectangular waveform supplied to said thick-filmheater differs in duration of supply in the respective modes.
 6. Arewritable medium recording apparatus according to claim 1, wherein theerasing means and the image forming means are connected to each other,and said erasing means and said image forming means are driven by asingle driving means.
 7. A rewritable medium recording apparatusaccording to claim 6, wherein the erasing means and the image formingmeans are rotatably mounted.
 8. A rewritable medium recording apparatusaccording to claim 7, wherein a load applied to the rewritable recordingmedium is set such that a load on The image forming means side exceedsthat on the erasing means side.
 9. A rewritable medium recordingapparatus according to claim 6, wherein discharge means is provided inthe travelling path for card.